An exemplary prior art unfurlable rescue ladder is sold by Guardian Fall Protection Inc. of Kent, Wash., marketed as the “rapid deployment rescue ladder.” It is used for rescuing fallen workers, such as in the construction industry. The ladder is light in weight, typically formed entirely or at least primarily of a fabric material, and is easily rolled up or folded for compact stowage in a weather resistant carrying container. The ladder is unfurled for use by another worker seeking to assist the fallen worker. If the fallen worker is not able to climb up the ladder, the worker who deployed the ladder can use it to climb down to assist the fallen worker.
Similar light weight, unfurlable ladders are used for mountain/rock climbing. An example is the “8-Step Ladder Aider” marketed by Metolius Mountain Products, Inc. of Bend, Oreg. The ladder aider, or simply “aider,” is typically anchored to an “ascender,” a device that is fitted securely around a rope the climber climbs. The rope has been previously positioned and anchored so as to hang down from the top of the climbing objective, and so it is called a “top rope.” The ascender is adapted to slide on the rope in one direction only, being prevented by friction from sliding in the reverse direction, and is oriented for climbing so that its sliding direction is upward. The climber wears a harness that is attached via a lanyard to the ascender. As the climber climbs the rope, the climber drags the ascender up the rope, the aider along with it. As the ascender captures the climber's progress by resisting downward sliding, the climber may step on the rungs of the aider and use it as a climbing assist.
A device known as a “progress capture pulley” is also sometimes used in mountain/rock climbing, and is often used in construction, for hauling equipment. A rope is passed over a sheave and a cam allows the rope to feed through the pulley in one direction but not the other.